Capsule Endoscopy Less Effective Than Colonoscopy in Detecting Lesions

Capsule Endoscopy is a procedure worthy of a scene in a futuristic movie; the patient swallows a vitamin-sized capsule containing a tiny wireless camera, and as the capsule travels through the digestive tract, it takes thousands of color pictures that are transmitted to a recorder worn around the waist. These images are then transferred to a computer with special software that strings the images together to create a video, which the doctor can then view to look for abnormalities within the digestive tract, particularly in the small intestine, an area that cannot be reached by more traditional endoscopy procedures. And while the capsule also provides good visualization of the colon, European researchers say it isn’t as effective in detecting pre-cancerous colon lesions and cancer as conventional colonoscopy.

Dr. Andre Van Gossum, from Erasme University Hospital, Brussels, Belgium, and colleagues compared the two procedures in a multicenter study of 328 patients with known or suspected colon lesions. Capsule endoscopy, using the PillCam COLON capsule manufactured by Given Imaging, was performed first, and then after the capsule was excreted, or at least 10 hours later, standard colonoscopy was performed. The researchers found that capsule endoscopy achieved a sensitivity rate of 64 percent and a specificity of 84 percent in detecting polyps at least 6mm in size. For identifying advanced polyps, rates were 73 and 79 percent, respectively. The capsule’s sensitivity depended largely on the cleanliness of the colon.

In addition, capsule endoscopy failed to detect malignancies in 5 of the 19 patients for whom colonoscopy identified. “This study shows that capsule endoscopy is a safe method of visualizing the colonic mucosa through colon fluids without the need for sedation or insufflation,” the researchers said. “However, the sensitivity of capsule endoscopy for detecting colonic polyps, advanced adenomas, and colorectal cancer was relatively low in comparison with colonoscopy.” They concluded that “the use of the colon capsule cannot be recommended at this stage for colon screening.”

In an editorial accompanying the study, Dr. Michael Bretthauer of Oslo University Hospital in Norway points out several other reasons why the procedure should not, at present, be recommended. One is its high cost. At approximately $1,150, capsule endoscopy is no lower than the price of conventional colonoscopy or computed tomographic colonography. Another is that it requires a more extensive bowel-cleansing regimen compared with colonoscopy and CT colonography.

In contrast, Dr. Douglas Rex, Professor of Medicine at the Indiana University of Medicine in Indianapolis, points out that there are currently “many individuals who are unwilling or unable to undergo colonoscopy,” perhaps since preparing for the test can be uncomfortable or because the procedure requires anesthesia or sedation. He says that “with technical improvements in the capsule and improvements in bowel cleansing, the capsule could become a safe and effective method to detect colon polyps in these patient populations.”

Dr. Felice Schnoll-Sussman, director of research with the Jay Monahan Center for Gastrointestinal Health at the New York-Presbyterian Hospital/Weill Cornell Medical Center in New York City, agrees that, despite deficiencies in identifying both polyps and cancers, the capsule does have value. “I think that in certain patient populations—those incapable of undergoing a colonoscopy because they are very difficult to sedate, or those that are just not willing to undergo a colonoscopy—this may be an appropriate alternative,” she said. “But patients will have to weigh the options, recognizing that the accuracy of colon capsule detection is lower.”

Though not approved for use in the U.S., the first-generation version of PillCam COLON is now commercially available in Europe, Asia, Latin America, Canada and Australia. Homi Shamir, CEO and President of Given Imaging, says they “are working closely with leading gastroenterologists to develop our second-generation PillCam COLON with the goal of increasing its sensitivity and simplifying the procedure for patients who are unwilling or unable to undergo a colonoscopy procedure.” He says the new version is currently advancing through clinical trials in Israel and could be unveiled in Europe at the Gastro 2009 conference this fall.

The findings were published in the July 16 issue of the New England Journal of Medicine.


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